The present invention relates to a semiconductor device and a manufacturing method thereof, and can be preferably utilized in a semiconductor device using, for example, a nitride semiconductor.
In recent years, semiconductor devices, using a group III-V compound having a bandgap larger than that of silicon (Si), have been attracting attention. Among them, a MISFET using gallium nitride (GaN) has advantages that: 1) a breakdown electric field is large; 2) electron saturation velocity is large; 3) a thermal conductivity is large; 4) a good heterojunction can be formed between AlGaN and GaN; 5) the gallium nitride is non-toxic and highly safe; and the like.
For example, each of Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2007-234986) and Patent Document 2 (International Publication No. 2006/022453) discloses a GaN-based field effect transistor having an AlN barrier layer. In the field effect transistor, an SiN insulating film is used as an insulating film for an element surface.